1. Field of the Invention
This invention relates generally to chairs having flexible, articulated backrests and more particularly, to a novel chair frame having upper and lower backrest frame parts conjoined by flexible spring means.
2. Description of the Prior Art
Chairs having articulated, flexible backrest parts for achieving desired support and comfort for the user are known in the art. Such chairs are used, for example, in banquet and conference facilities where back comfort for the seated attendees is so desirable. Typically, such chairs are stackable and have molded backrest parts and peripheral frame parts of hollow construction to enable interconnection of upper and lower backrest parts which are flexible. Various flexible spring arrangements for joining the upper and lower backrest parts of such chairs are shown in the following U.S. Patents:
______________________________________ 2,020,028 3,351,378 2,587,822 4,084,850 2,732,005 4,157,203 3,183,034 4,333,683 3,203,731 ______________________________________
The chairs disclosed in the listed patents include articulated, flexible backrests which are of complex construction and relatively involved to install. Simplicity and economy of construction and installation for such chairs which are used in great numbers is a very important and desirable objective. Additionally, it is important to provide a chair construction in which the flexing parts are reliable and capable of repeated use without breaking and which incorporate safety features to prevent sudden failure of the flexable frame parts in the event such parts do fracture or otherwise break after extensive and repeated use. Such safety features are important to prevent possible injury to the user of the chair.